Bellows

ABSTRACT

A method and apparatus for forming convolutions in a tube, the method including the steps of securing a reinforcing ring to each end of a tube, supporting one end of the tube, arranging rollers on each side of the wall of the tube and forming a convolution in the wall of the tube by rotating the tube with respect to the rollers; the convolution so formed extending radially outwardly with respect to the remainder of the tube wall.

United States Patent [56] References Cited UNITED STATES PATENTS 1,597,206 8/1926 Mallory .1 72/105 1,614,563 1/1927 Leach et al. 72/105 l,823,532 9/1931 Clifford 29/454 3,143,794 8/1964 Martin-Hurst 29/454 3,435,651 4/1969 Mclnnis 29/454 Primary Examiner-Lowell A. Larson AttorneyNorris & Bateman 1 70 I 1 u l E c I a 1 5 E 17 x i i 9 PATENTED JUL27 I97! INVENTOR GORDON CHARLES H0111 GORDON CHARLES l 10 L'I BELLOWS This invention relates to bellows and to a method and apparatus for making bellows from tubular material.

lt has been previously proposed to form bellows by mandrel rolling whereby convolutions have been formed in a tube by means of mandrels to form a bellows which can be incorporated in a pipeline so as to constitute an expansion joint. The disadvantage with mandrel rolling is that the convolutions formed by the mandrel extend both radially outwardly and inwardly with respect to the tube. The inwardly extending convolutions thus constitute a partial barrier to the flow of fluid in a pipeline in which the bellows is connected. Such a barrier not only restricts the flow of fluid therethrough but can also cause turbulence which is undesirable.

In order to overcome this disadvantage and provide a bellows in which all of the convolutions extend radially outwardly, it has been proposed to mount a tube on a drum and to cold-roll the convolutions in the tube while the latter is mounted on the drum. This arrangement certainly prevents the convolutions from extending inwardly but the disadvantage is that the tube must fit closely over the drum. Thus, a separate drum is required for each diameter of tube from which it is desired to produce a bellows. Further, the drums have to be machined very accurately to accommodate a tube of the correct size which means that the drums are expensive. Therefore, although the drum arrangement is capable of producing a bellows in which all of the convolutions extend radially outwardly thus avoiding the barrier formed when the bellows are formed by mandrel rolling as above described, this arrangement is very expensive because of the high cost of the drums and the large number required.

The present invention aims to provide a method of and an apparatus for forming convolutions in a tube which can be used for'tubes of varying sizes without the use of drums and in which all of the convolutions extend substantially radially outwardly.

According to the invention, there is provided a method of making bellows, the method including the steps of securing a reinforcing ring to each end of a tube, supporting one end of the tube, arranging rollers on each side of the wall of the tube and forming a convolution in the wall of the tube by rotating the tube with respect to the rollers; the convolution so formed extending radially outwardly with respect to the remainder of the tube wall.

The invention also extends to an apparatus for performing the method according to the invention, the apparatus comprising means for supporting one end of a tube having reinforcing rings secured to each end thereof, rollers arranged to bear against the inside and outside surfaces of the walls of the tube and means for rotating the tube, the rollers being arranged to form a convolution in the wall of the tube as the tube is rotated and the convolution extending radially outwardly with respect to the tube.

The tube is preferably rotated by the rollers which are themselves rotated by suitable rotation drive means. However, separate drive means for rotating the tube may be provided if desired. In the latter case, the rollers will normally be free rolling and be rotated by virtue of their engagement with the wall of the tube.

The apparatus preferably comprises a single roller arranged to bear against the inside surface of the wall of the tube and a pair of rollers arranged to bear against the outside surface of the wall of the tube, the singe inner roller being movable towards the two outer rollers whereby the part of the tube wall against which the single roller bears is forced between the two outer rollers to form a convolution in the wall of the tube as said tube is rotated.

Further, the apparatus desirably includes a series'of rollers adapted to be placed in turn on their respective spindles to form convolutions in a tube in stages.

The invention also extends to bellows made according to the method or with the apparatus of the present invention.

The reinforcing rings impart rigidity to the tube and ensure that the tube is of circular cross section before rolling begins. The rings may be tack welded at intervals to the tube and removed after the convolutions have been formed in said tube. Alternatively, the reinforcing rings may form part of pipe ends adapted to be connected to adjacent pipe lengths in the line for which the bellows is intended. In the latter case, the reinforcing rings will be welded or otherwise secured more firmly to the tube ends.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which:

FIG. I shows one embodiment of an apparatus according to the invention with a tube fitted thereon and showing the first step in forming convolutions in the tube;

FIGS. 2 and 3 show successive steps in forming convolutions in the tube; and

FIG. 4 shows the final step in forming the convolutions in the tube.

In the drawings, like parts are denoted by like reference numerals.

Referring to the drawings, the apparatus comprises a machine table 1 from which a pair of spindles 2, 3 extend substantially vertically upwards. The table 1 has a substantially flat upper surface for receiving one end of a tube 4 in which convolutions are to be formed. The spindle 2 is located inside the tube and is provided with a single convolution forming roller 5. The other spindle 3 is located outside the tube 4 and is provided with a pair of convolution forming rollers 6, 7 and a pair of guiding rollers 8, 9. The rollers 6, '7 are arranged to cooperate with the roller 5 and the guiding rollers 8, 9 bear against the ends of the tube and prevent deformation of the tube except at the area where a convolution is to be formed. The rollers are axially displaceable on the spindles 2, 3 so as to form a series of convolutions as hereinafter described.

The spindles 2, 3 are movable with respect to the machine table 1 to accommodate tubes of different diameters. Further, the spindles are connected to a drive means through a differential gear box (not shown) which permits synchronization of the peripheral speeds of the rollers.

In order to produce a bellows, a tube 4 having a reinforcing ring 10 secured to each end is mounted on one end on the machine table 1 and the outer spindle 3 is moved so that the outer rollers 6, 7, 8 and 9 bear against the outer surface of the tube wall. The spindle 3 is then firmly clamped in position so that it is only capable of rotational movement. The inner spindle 2 is positioned so that its roller 5 bears against the inner surface of the tube wall but the inner spindle 2 is mounted so that it is capable of controlled movement towards the outer spindle 3. The spindles 2, 3 are then driven in opposite directions and the associated rollers impart rotational move ment to the tube 4. i i

As the tube rotates, the inner spindle 2 is moved progressively towards the outer spindle 3. The tube wall in the region of the inner roller 5 is thus forced radially outwardly by said roller and the two outer rollers 6 and 7, which bear against the outer surface of the tube wall and which are laterally immovable, cause the tube ends to move axially inwardly so the inner roller 5 moves towards the outer rollers: 6 and 7. The guiding rollers 8, 9 ensure that the ends of the tube do move radially outwardly and a convolution 12 is thus formed in the tube with the inner roller 5 bearing against the inside face of the convolution and the sides of the outer rollers bearing against the wall of the tube on both sides of the convolution as shown in H0. 1.

When the inner roller 5 has moved to its fullest extent permitted by the tube wall between the roller 5 and rollers 6 and 7, the convolution 11 has been fully formed in the tube and the drive to the spindles 2, 3 is disconnected so that the rollers 5-9 and hence the tube 4 cease to rotate. The inner spindle 2 is then moved away from the outer spindle 3 until the roller 5 is clear of the convolution 11. The rollers 5, 6 and 7 are then axially displaced with respect to the tube and the process repeated to form another convolution 12 in the tube 4 as shown in FIG. 1. This process may be again repeated to form a series of convolutions in the tube without having to move the tube from the supporting surface on table 1. FIG. 1 shows four such convolutions ll, 12, 13 and 14 in the tube 4.

Having formed the desired number of convolutions in the tube, the flat faced rollers 7 are removed from their respective spindles and replaced by radiused rollers 15, 16 and 17 respectively. The spindles 2, 3 are driven as before and.

spindle 2 moved further towards spindle 3 as the tube rotates. The rollers 15, 16 and 17 deepen the convolutions 11 to 14 to form convolutions 21 to 24 as shown in FIGS. 2 and 3.

The rollers 15-17 are then replaced by still more radiused convolution-forming rollers 25, 26 and 27 respectively to deepen convolutions 21 to 24 to form convolutions 31 to 34 as shown in FIGS. 3 and 4.

Finally, rollers 25-27 are replaced by still further radiused convolution-forming rollers 35, 36 and 37 respectively which form the final shape of the convolutions as shown by 41 and 42 in FIG. 4.

instead of resting on the upper surface of the machine table 1, one end of the tube 4 may if desired be supported on a number of rollers (not shown) which allow the tube to rotate when said tube is driven by the convolution-forming rollers. The support rollers are desirably adjustable so that they can serve to support a tube of any diameter within predetermined limits. it has been found that with tubes of relatively large diameters it is desirable to use rollers to reduce friction but with relatively small diameter tubes a flat surface such as the upper surface of the machine table is satisfactory.

The speed of rotation of the spindles and hence the rollers is adjusted according to the diameter of the tube used. It will be appreciated that as the diameter of tube increases the speed of rotation of the spindles increases correspondingly.

The inner spindle 2 is desirably moved towards the outer spindle 3 by means of an air cylinder operated through a solenoid valve with a needle valve interposed in the circuit to control the rate of approach of the inner spindle to the outer spindle.

Guiding rollers may also be provided on the inner spindle and be arranged to bear against the reinforcing rings at the end portions of the inner surfaces of the tube. These inner guiding rollers, in conjunction with the guiding rollers provided on the outer spindle, ensure that the end portions of the tube remain substantially parallel to each other and further ensure that all of the convolutions extend substantially radially outwardly.

The guiding rollers provided on the outer spindle may have a larger diameter than the convolution-forming rollers provided on the same spindle. This arrangement further ensures that the convolutions extend radially outwardly with respect to the tube because the tube wall is deformed radially outwardly by the inner convolution-fuming rollers to some extent before the outer forrning rollers engage the tube wall.

Instead of replacing the sets of rollers on the spindles for deepening the convolutions, the spindles themselves may be replaced. In this case the rollers will be kept on their respective spindles but will still, of course, be axially movable with respect thereto.

It is also envisaged to form convolutions in a tube in one operation using only one set of rollers. Such an arrangement forms the subject of our copending patent application number.

It will be seen that with the apparatus according to the invention, bellows of any desired diameter can be obtained in which all of the convolutions extend substantially radially outwardly. Moreover, although it has been described with reference to single ply tubes, the invention is equally applicable to so-called multi-ply tubes.

1 claim:

1. A method of making bellows, the method including the steps of securing a reinforcing ring to each end of a tube, supporting one end of the tube, arranging rollers on each side of the wall of the tube and forming a convolution in the wall of the by rotating the tube with respect to the rollers; the convolution so formed extending radially outwardly with respect to the remainder of the tube wall.

2. A method as claimed in claim 1, wherein a single roller is arranged to bear against the inside of the tube wall and a pair of rollers are arranged to bear against the outside of the tube wall, and wherein a convolution is formed in the tube wall by moving the single roller towards the pair of rollers during rotation of the tube.

3. A method as claimed in claim 1, including the further step of removing the reinforcing rings from the end of a tube after bellows have been made from said tube.

4. The method defined in claim 1, wherein said reinforcing rings take the form of pipe ends adapted to to connected to adjacent pipe lengths in a line for which the bellows is intended.

5. A method of making bellows comprising the steps of supporting a tube for rotation about a vertical axis, providing at least one forming roller within the tube for peripherally engaging the tube wall at a region disposed between two adjacent outer forming rollers peripherally engaging the tube wall at said region and moving said inner forming roll substantially radially outwardly while relatively rotating said inner and outer rollers to form an externally projecting convolution in said wall at said region, said tube being free to move axially as the convolution is being formed.

6. The method defined in claim 5, wherein said tube is provided with axially spaced internal reinforcing rings, and rotatable guide rollers are mounted coaxially with said outer forming rollers in peripheral engagement with the outer side of said tube opposite the respective rings, said ring and guide roller sets being disposed adjacent opposite ends of the tube wall being formed with said convolution.

7. Apparatus for imparting bellows configuration to the wall of a substantially cylindrical tube comprising means for mounting the tube for rotation about its axis, a first forming roller adapted to be disposed within the tube and rotatable about an axis parallel to the tube in peripheral engagement with the inner side of the tube, second and third forming rollers adjacently mounted in fixed axially spaced relau'on and adapted to be rotated about an axis parallel to the tube in peripheral engagement with the outer side of said tube, said first forming roller being rotatable relative to said tube and located to engage the tube in a region axially between said second and third forming rollers, and said first forming roller being substantially radially displaceable outwardly within said tube toward said tube wall region to form an outwardly extending convolution in said tube wall between said second and third forming rollers during said relative rotation.

8. The apparatus defined in claim 7, wherein fourth and fifth guide rollers of the same diameter are mounted to rotate on the same axis as said second and third rollers in peripheral engagement with the outer side of said rollers, said fourth and fifth rollers being mounted at axially opposite sides of said second and third forming rollers.

9. The apparatus defined in claim 7, wherein at least one of said guide rollers is axially adjustable toward and away from said forming rollers.

10. The apparatus defined in claim 7, wherein said forming rollers are all axially adjustable for forming convolutions in different regions along said tube.

11. The apparatus defined in claim 7, wherein said forming rollers are removable and replaceable by forming rollers of differing contour adapted for progressively forming each convolution.

12. The apparatus defined in claim 7, wherein said .tube and roller axes are all substantially vertical, and the lower end of said tube is axially supported for rotation of the tube about its axis while the upper end of said tube is free to dispace toward the lower end as convolutions are formed along said tube wall.

13. The apparatus defined in claim 7, wherein said tube is supported for free rotation and said inner and outer forming rollers are mounted on spindles adapted to be oppositelyrotated 

1. A method of making bellows, the method including the steps of securing a reinforcing ring to each end of a tube, supporting one end of the tube, arranging rollers on each side of the wall of the tube and forming a convolution in the wall of the by rotating the tube with respect to the rollers; the convolution so formed extending radially outwardly with respect to the remainder of the tube wall.
 2. A method as claimed in claim 1, wherein a single roller is arranged to bear against the inside of the tube wall and a pair of rollers are arranged to bear against the outside of the tube wall, and wherein a convolution is formed in the tube wall by moving the single roller towards the pair of rollers during rotation of the tube.
 3. A method as claimed in claim 1, including the further step of removing the reinforcing rings from the end of a tube after bellows have been made from said tube.
 4. The method defined in claim 1, wherein said reinforcing rings take the form of pipe ends adapted to to connected to adjacent pipe lengths in a line for which the bellows is intended.
 5. A method of making bellows comprising the steps of supporting a tube for rotation about a vertical axis, providing at least one forming roller within the tube for peripherally engaging the tube wall at a region disposed between two adjacent outer forming rollers peripherally engaging the tube wall at said region and moving said inner forming roll substantially radially outwardly while relatively rotating said inner and outer rollers to form an externally projecting convolution in said wall at said region, said tube being free to move axially as the convolution is being formed.
 6. The method defined in claim 5, wherein said tube is provided with axially spaced internal reinforcing rings, and rotatable guide rollers are mounted coaxially with said outer forming rollers in peripheral engagement with the outer side of said tube opposite the respective rings, said ring and guide roller sets being disposed adjacent opposite ends of the tube wall being formed with said convolution.
 7. Apparatus for imparting bellows configuration to the wall of a substantially cylindrical tube comprising means for mounting the tube for rotation about its axis, a first forming roller adapted to be disposed within the tube and rotatable about an axis parallel to the tube in peripheral engagement with the inner side of the tube, second and third forming rollers adjacently mounted in fixed axially spaced relation and adapted to be rotated about an axis parallel to the tube in peripheral engagement with the outer side of said tube, said first forming roller being rotatable relative to said tube and located to engage the tube in a region axially between said second and third forming rollers, and said first forming roller being substantially radially displaceable outwardly within said tube toward said tube wall region to form an Outwardly extending convolution in said tube wall between said second and third forming rollers during said relative rotation.
 8. The apparatus defined in claim 7, wherein fourth and fifth guide rollers of the same diameter are mounted to rotate on the same axis as said second and third rollers in peripheral engagement with the outer side of said rollers, said fourth and fifth rollers being mounted at axially opposite sides of said second and third forming rollers.
 9. The apparatus defined in claim 7, wherein at least one of said guide rollers is axially adjustable toward and away from said forming rollers.
 10. The apparatus defined in claim 7, wherein said forming rollers are all axially adjustable for forming convolutions in different regions along said tube.
 11. The apparatus defined in claim 7, wherein said forming rollers are removable and replaceable by forming rollers of differing contour adapted for progressively forming each convolution.
 12. The apparatus defined in claim 7, wherein said tube and roller axes are all substantially vertical, and the lower end of said tube is axially supported for rotation of the tube about its axis while the upper end of said tube is free to dispace toward the lower end as convolutions are formed along said tube wall.
 13. The apparatus defined in claim 7, wherein said tube is supported for free rotation and said inner and outer forming rollers are mounted on spindles adapted to be oppositely rotated. 